ORDER OF BATS 



319 



General Description. — Smallest of the North Amer- 

 ican Bats. Head small ; ears short, tapering to a nar- 

 row rounded tip and longer than broad ; tragus rather 

 short, very blunt and curved forward; body small; feet 

 small; interfemoral membrane of moderate size, sparsely 

 haired on upper surface ne.xt to body ; face and ears 

 bare, black; pelage, pale drab. A swift-flying, delicately 

 built Bat. 



Dental Formula. — Incisors, — ; Canines, ; Pre- 



molars. ^'£^' ; Molars, ^^:;:^^34. 



Pelage. — Adults : Sexes identical ; seasonal varia- 

 tion slight, .^bove, pale drab ; below, brownish-white ; 

 all the fur blackish at base ; membranes, dull black. 

 Young: Similar to adults. 



Measurements. — Total length, 2.8 inches ; tail verte- 

 brae, 1.2 inches; ear from crown, .4 inch; expanse of 

 wing, 7.9 inches. 



LEAST BROWN BAT 



Pipistrellus hesperus iH. Allen) 



Range.— Western United States from Texas to the 



The Least Brown Bat deserves special atten- 

 tion because of its diniintitive and graceful aj)- 

 pearance. It is the smallest of otir native Bats, 

 and approaches the Pygmy Shrew in the dis- 

 tinction of being one of our smallest mammals 

 of whatever order. Its body, not measuring the 

 tail, is only abotit one and one-half inches long. 

 But on account of its expanse of wing — nearly 

 eight inches — this small size of body is not 

 appreciated. This Bat has the delicate nie- 



Pacific Coast. 

 Food. — Insects of flying varieties. 



Rel.wed Species 



Least Brown Ba.t.— Pipistrellus hesperus hesperus 

 (H. Allen). Typical animal of the above description. 

 Western United States. 



Georgian Bat.^ Pipistrellus subflavus subflavus (F. 

 Cuvier). Larger than hesperus; general color, yellow- 

 ish-brown. Eastern United States, west to Iowa and 

 southern Texas. 



Dusky Least Bat. — Pipistrellus subflaz'us obseurus 

 Miller. Color duller and less yellow than that of 

 Georgian Bat ; pale wood-brown above. Central and 

 eastern New York. 



chanism of a watch. It is quick, nervous, alert, 

 and agile. It appears to be among the brightest 

 in mental development. While closely related to 

 the little Brown Bats, the Least Brown Bat is 

 even more delicate. It may be readily told from 

 members of the genus Myotis by the shape of 

 the ear and the extent of furring of the interfem- 

 oral membrane as well as by its size. Three 

 species of this genus are found north of the 

 Rio Grande. 



RED BAT 

 Lasiurus borealis ( Miiller) 



General Description. — About the size of the Com- 

 mon Brown Bat but coloration strikingly different. 

 Head small ; nostrils simple ; ears broad, rounded at tip. 

 hairy ; tragus rouglily triangular in outline : body small ; 

 wings large; tail long, nearly half of total length and 

 completely included in interfemoral membrane, which is 

 covered with fur on upper surface ; general color bright 

 reddish-brown. A common Bat in the eastern United 

 States. 



Dental Formula 



molars, 



; Molars,^—' 

 ' 3—3 



Incisors, 5 — - : Canines. 

 3—3 



Pre- 



Pelage.— Adults : Sexes identical; no noticeable 

 seasonal variation. Color variable but ranging from 

 bright reddish-brown to yellowish-red or yellowish ; a 

 small whitish patch in front of shoulder; pelage long 

 and soft. Young: Similar to adults, but not as bright 

 until nearing maturity. 



Measurements. — Total length, 4.2 inches ; tail verte- 

 brae, 2 inches; hind foot, .3 inch; wing expanse, 12 

 inches. 



Range.— Eastern North America from Canada to 

 Florida, and Texas west to Colorado. 



Food. — Insects. 



Remarks.— This strikingly-colored Bat may be 

 known at once from all the other Bats by its peculiar 

 markings; and all the members of the genus may be 

 told by the furred interfemoral membrane. There are 

 four species and subspecies of this genus found north 

 of the Rio Grande. 



Related Species 



Red Bat.— La.?mrM.y borealis borealis (MUller). 

 Typical animal of the above description. Eastern North 

 .\merica south to Florida, west to Colorado. 



Florida Red Rat.— Lasiurus borealis seininolus 

 (Rhoads). Similar to Red Rat but general color 

 mahogany-brown. South Carolina to southern Texas. 



Western Red Bat. — Lasiurus borealis teliotis (H. 

 .\llen). Smaller than Red Bat with shorter ears. Cali- 

 fornia. 



Hoary Bat. — Lasiurus einereus (Beauvois). See 

 special synopsis. 



